KR20090066595A - Apparatus and method to control brightness of led using digital code - Google Patents

Abstract

An illumination control device using a digital code and a controlling method thereof are provided to reduce spurious characteristics according to generation of a driving voltage by converting a control signal to a digital code. An illumination control device using a digital code includes an illumination control unit(210), a digital code generation unit(220), a digital conversion unit(230), and a D/A converter unit(240). The illumination control unit generates a control signal for controlling brightness of illumination devices. The digital code generation unit generates a digital code corresponding to the control signal. The digital conversion unit randomizes the digital code at each of cycles. The D/A converter unit generates a driving voltage by converting the randomized digital code to an analog code.

Description

Lighting control device and method using digital code {Apparatus and Method to control brightness of LED using Digital Code}

The present invention relates to a lighting control apparatus and method for controlling a plurality of lighting brightness and colors, and more particularly, by converting a control signal for controlling lighting to a corresponding digital code and then randomizing the digital code The present invention relates to a lighting control apparatus and method using a digital code that can reduce spurious characteristics by generating a driving voltage having aperiodicity.

In general, lighting is a device that brightens a dark place to be recognized by the human eyes, mainly LED (Light Emitting Diode), fluorescent and incandescent lamps are mainly used.

Such lighting may control the brightness and its color according to the magnitude of the driving voltage, and the control method may control the brightness and the color of the lighting by adjusting a duty width of a pulse width modulation (PWM) signal.

Hereinafter, a lighting control apparatus according to the related art will be described with reference to related drawings.

1 is a block diagram of a lighting control apparatus according to the prior art, Figure 2 is a diagram illustrating the duty width control of the PWM signal according to the prior art.

First, as shown in FIG. 1, the lighting control apparatus according to the related art is composed of a lighting control stage 110, a PWM signal generating stage 120, a driving voltage generating stage 130, and an lighting stage 140. do.

Here, the lighting control unit 110 is connected to the PWM signal generating unit 120, and controls the brightness and color of the plurality of first to n-th illumination (140a ~ 140n) provided in the illumination stage 140 A control signal S for generating is generated.

In this case, the controller 110 receives a current flowing through each illumination of the lighting unit 140 and compares it with a preset reference value. When the feedback current is smaller than the reference value, the control unit 110 increases the magnitude of the driving voltage Vc. The control signal S is generated, and when the feedback current is larger than the reference value, the control signal S for reducing the magnitude of the driving voltage Vc is generated.

In addition, the PWM signal generating unit 120 is composed of a plurality of first to n-th PWM signal generating unit (120a ~ 120n), each of the plurality of first to n-th PWM signal generating unit (120a ~ 120n) It is controlled by the control signal S and outputs a PWM signal P for increasing or decreasing the magnitude of the driving voltage Vc.

In this case, as illustrated in FIG. 2, which is an explanatory view of the duty width control of the PWM signal P, the first to nth PWM signal generators 120a to 120n have the driving signal Vc. In the case of a signal for reducing the magnitude of), the width of the duty-on period of the PWM signal P is reduced and output. In addition, when the control signal S is a signal for increasing the magnitude of the driving voltage Vc, the n th to n th PWM signal generators 120a to 120n define the width of the duty-on period of the PWM signal P. Increase the output.

Then, each of the first to n-th driving voltage generators 130a to 130n of the driving voltage generator 130 receives the PWM signal P whose width of the duty-on period is controlled and corresponds to the corresponding driving voltage ( By outputting Vc), the brightness of the plurality of first to nth illuminations 140a to 140n can be controlled.

However, the lighting control apparatus according to the prior art having the above configuration has the following problems.

Conventional lighting apparatus generates a PWM signal (P) having a predetermined period to drive the plurality of first to n-th illumination (140a ~ 140n). In this case, the PWM signal P controls the driving voltage Vc by increasing or decreasing the width of the duty-on period by the control signal S, but has a constant period so that spurious occurs. there was.

In addition, due to the spurious generated when driving a plurality of lights (140a ~ 140n) there is a problem that the noise is generated in the lighting control device is lowered the lighting efficiency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and by converting a control signal for controlling illumination into a digital code corresponding thereto, the digital code is randomized to generate a driving voltage having aperiodicity, thereby reducing spurious characteristics. It is an object of the present invention to provide a lighting control apparatus using the digital code and a method thereof.

Lighting control apparatus using a digital code according to the present invention for achieving the above object, the lighting control stage for generating a control signal for controlling a plurality of illumination brightness; A digital code generator for generating a digital code corresponding to the control signal; A digital conversion stage for randomizing the digital code at each period; And a D / A converter stage for generating a driving voltage by converting the digital code randomized through the randomization stage into an analog. Accordingly, the lighting control device according to the present invention can reduce the spurious characteristics by supplying a driving voltage having aperiodicity and has the effect of improving the efficiency of lighting.

At this time, the digital code is characterized by using a thermometer code.

The D / A converter stage may convert the randomized digital code into an analog to generate a driving voltage having aperiodicity, and the illumination may be an LED.

In addition, the lighting control method using a digital code according to the present invention for achieving the above object, a) generating a control signal for controlling a plurality of illumination brightness; b) generating a digital code corresponding to the control signal; c) randomizing the digital code at each period; d) converting the randomized digital code into an analog to generate a driving voltage; And e) supplying the generated driving voltage to a plurality of lights.

At this time, the digital code generated in step b) is characterized in that the thermometer code.

In addition, in step d), a driving voltage having aperiodicity is generated every cycle, and the plurality of lights are LEDs.

Lighting control apparatus and method using a digital code according to the present invention, by converting a control signal for controlling the illumination to a corresponding digital code and randomize the digital code to generate a driving voltage having aperiodicity There is an effect that can reduce the spurious characteristics.

In addition, the lighting control apparatus and method according to the present invention, by controlling the plurality of illumination brightness and color by using the driving voltage having the aperiodic, it is possible to improve the efficiency of illumination by preventing the generation of spurious It works.

Details of the configuration, method and effects of the lighting control device using the digital code according to the present invention will be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

Lighting control

3 is a block diagram illustrating a lighting control apparatus using a digital code according to the present invention, and FIGS. 4A and 4B are graphs showing a random code and a driving voltage according to the present invention.

First, as shown in FIG. 3, the lighting control apparatus using the digital code according to the present invention includes a lighting control stage 210, a digital code generation stage 220, and a digital conversion stage 230. And a D / A converter stage 240 to control the brightness of the lighting stage 250 and the color of the lighting stage 250 including the plurality of first to n-th illuminations 250a to 250n.

Here, the lighting control unit 210 is connected to the digital code generation terminal 220, and controls the brightness and color of the plurality of first to n-th illumination (250a ~ 250n) provided in the illumination stage 250 A control signal S for generating is generated. Preferably, the first to nth illuminations 250a to 250n are LEDs (Lighting Emitting Diodes).

The digital code generator 220 is composed of a plurality of first to n-th digital code generators 220a to 220n, is connected to the lighting control unit 210 and the digital converter 230, and the control A digital code (Dc: digital code) corresponding to the signal S is generated.

In this case, the control signal S is a signal including illumination brightness information for controlling the brightness and color of the first to n-th illumination (250a ~ 250n). As shown in Table 1 below, assuming that the control signal (S) can be expressed from 0 to 7 steps, each step represents a step of brightness and color information of the plurality of lights 250a to 250n. .

In this case, when the control signal S is 0, the signal is very dark. If the control signal S is 7, the signal is very bright. Meanwhile, in the present invention, the control signal (S) is limited to 0 to 7 steps, which is an embodiment for clearly describing the present invention, and the lighting control apparatus according to the present invention may adjust the brightness level of the control signal (S). It may be set within the range of 0 to 255.

Each of the first to n-th digital code generators 220a to 220n receiving the control signal S as described above is digitized to a code corresponding to the control signal S. FIG. For example, if the control signal S includes brightness information of four levels, the first digital code generator 220a generates a digital code Dc of '0001111', and the control signal S If includes 7 levels of brightness information, the first digital code generation unit 220a generates a digital code (Dc) of '1111111'.

In particular, the digital code generation stage 220 uses a thermometer code as the digital code Dc.

In this manner, each of the first to n-th digital code generators 220a to 220n generates a digital code Dc corresponding thereto by the applied control signal S, and generates the generated digital code Dc. ) Is transmitted to the digital converter 230.

The digital converter 230 includes a plurality of first to n-th randomizers 230a to 230n, and is connected to the digital code generator 220 and the D / A converter 240, and generated. The digital code Dc is randomized.

Here, the first randomizer 230a is connected to the first digital code generator 220a to receive the digital code Dc from the first digital code generator 220a. In this case, when the digital code Dc is applied, the first randomization unit 230a randomizes the digital code Dc and outputs a random code RDc.

In this case, the random code RDc generated by the first randomization unit 230a may be represented as shown in Table 2 below.

As shown in [Table 2], when the control signal S is 6, the first digital code generator 220a generates a digital code Dc of '0111111' and the digital code Dc of the '0111111'. The first randomization unit 230a, which has received the Rx), randomizes the digital code Dc to generate a random code RDc of '1110111'.

In addition, when the control signal S is 3, the first digital code generator 220a generates a digital code Dc of '0000111' and receives the digital code Dc of '0000111'. The randomization unit 230a randomizes the digital code Dc to generate a random code RDc of '0010011'.

In this case, the randomization process is described only with respect to the first randomization unit 230a. However, since the second to nth randomization units 230b to 230n receive the same digital code Dc as the first randomization unit 230a. Will do the same.

The D / A converter stage 240 includes a plurality of first to n-th D / A converter units 240a to 240n and is connected to the digital conversion stage 230 and the lighting stage 250. The D / A converter stage 240 converts the random code RDc applied through the digital conversion stage 230 into an analog signal to provide a plurality of lights 250a to 250n provided in the lighting stage 250. Generates a driving voltage Vc for driving.

For example, when the control signal S output from the lighting control terminal 210 has six levels of brightness information, the digital code Dc has '0111111', and the random code RDc is Will have '1110111'.

Accordingly, the D / A converter stage 240 generates the driving voltage Vc of '1110111' in the section 'L1', as shown in FIG. 4A showing the driving voltage Vc, and then the next period. In the "L2" section, the driving voltage Vc corresponding to the randomized '1101111' is generated by the digital code Dc of '0111111'.

In addition, when the control signal S output from the lighting control stage 210 has four levels of brightness information, the digital code Dc is '0001111' and the random code RDc is '0110101'. Will have

Accordingly, as shown in FIG. 4B, the D / A converter stage 240 generates the driving voltage Vc of '0110101' in the 'L1' section, and in the 'L2' section, which is the next period. The digital code Dc of '0001111' generates a driving voltage Vc corresponding to '0111001' which is randomized.

In particular, even if the digital code (Dc) is randomized in every section as described above, the high level section is the same in every section, so that the brightness and color of the illumination can be kept constant at all times.

Therefore, the D / A converter stage 240 controls the brightness and the color of the illumination by generating a non-periodic driving voltage Vc at each cycle and supplying it to the plurality of lights 250a to 250n.

As described above, the lighting control apparatus using the digital code according to the present invention, in order to control the brightness and color of the plurality of lights (250a ~ 250n) and the driving voltage (Vc) having a different pattern of aperiodic period every cycle By supplying, there is an effect of reducing the spurious characteristics.

In addition, as the spurious characteristics are reduced, there is an advantage in that the efficiency of the plurality of lights 250a to 250n can be improved.

Lighting control method

Hereinafter, a lighting control method using a digital code according to the present invention will be described in detail with reference to FIGS. 3 and 4 as described above.

5 is a flowchart sequentially illustrating a lighting control method using a digital code according to the present invention.

First, as shown in Figure 5, the illumination control method using a digital code according to the present invention, generates a control signal (S) for controlling the brightness and color of the plurality of lights (250a ~ 250n) (S310) . The plurality of lights 250a to 250n may be light emitting diodes (LEDs).

After generating the control signal S, a digital code Dc corresponding to the generated control signal S is generated (S320).

At this time, the digital code (Dc) generated in the step S320 is a predetermined code by the user and is composed of codes that are separated from each other according to the control signal (S). In particular, it is preferable that the digital code Dc uses a thermometer code.

After generating the digital code Dc, the generated digital code Dc is randomized to generate a random code RDc (S330). In particular, in step S330, the digital code Dc is randomized every cycle to generate the random code RDc.

In this way, the random code RDc generated through the step S330 is converted into a driving voltage Vc having an analog aperiodicity (S340).

Then, the erection and color of the plurality of lights 250a to 250n may be controlled by supplying the analog driving voltage Vc to the plurality of lights 250a to 250n.

Lighting control method using a digital code according to the present invention as described above, in order to control the brightness and color of the plurality of lights (250a ~ 250n) the driving voltage (Vc) having a different pattern of aperiodic periods every cycle By supplying a plurality of lights 250a to 250n, there is an effect that the spurious characteristics can be reduced.

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications, and changes within the scope of the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It will be appreciated that such substitutions, changes, and the like should be considered to be within the scope of the following claims.

1 is a block diagram of a lighting control apparatus according to the prior art.

2 is an explanatory diagram of a duty width control of a PWM signal according to the prior art;

Figure 3 is a block diagram of a lighting control device using a digital code according to the present invention.

4A and 4B are graphs showing a random code and a driving voltage according to the present invention.

5 is a flow chart sequentially showing a lighting control method using a digital code according to the present invention.

<Description of Symbols for Major Parts of Drawings>

210: lighting control stage 220: digital code generation stage

230: digital conversion stage 240: D / A converter stage

250: lighting stage

Claims (8)

An illumination control stage for generating a control signal for controlling a plurality of illumination brightnesses; A digital code generator for generating a digital code corresponding to the control signal; A digital conversion stage for randomizing the digital code at each period; And A D / A converter stage for generating a driving voltage by converting a digital code randomized through the randomization stage into an analog; Lighting control device using a digital code comprising a. The method of claim 1, The digital code is a lighting control device using a digital code, characterized in that the thermometer code. The method of claim 1, The D / A converter stage converts the randomized digital code into an analog to generate a driving voltage having aperiodicity. The method of claim 1, The lighting control device using a digital code, characterized in that the LED. a) generating a control signal for controlling a plurality of illumination brightnesses; b) generating a digital code corresponding to the control signal; c) randomizing the digital code at each period; d) converting the randomized digital code into an analog to generate a driving voltage; And e) supplying the generated driving voltage to a plurality of lights; Lighting control method using a digital code comprising a. The method of claim 5, Digital code generated in step b) is a lighting control method using a digital code, characterized in that the thermometer code. The method of claim 5, And the driving voltage has aperiodicity in step d). The method of claim 5, The plurality of lights are lighting control method using a digital code, characterized in that the LED.

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